1. Field of the Invention
The invention relates to electrolytic capacitors and somewhat more particularly to aluminum electrolytic capacitors for rated voltages of at least 160 volts.
2. Prior Art
Electrolytic capacitors are known and generally consist of wound-on layers of an anode foil, the surfaces of which may be roughened and which is provided with a dielectric oxide layer, a cathode foil and spacing means between the cathode and anode foil which is saturated with an operating electrolyte.
One of the facts which determines the light yield in flashlight devices is the dissipation factor of the utilized flashlight electrolytic capacitor. Thus, by reducing the dissipation factor, it is possible to increase the light yield.
On the other hand, in modern useage, there has been an increasing demand to reduce the size of components, i.e., in electrolytic capacitors to increase the capacitance per unit volume. One means of achieving an increased capacitance is by utilizing anode foils having surfaces roughened to a greater extent. However, increased foil roughness causes an increase in the dissipation factor of the electrolytic capacitors. It is also known that the conductivity of an operating electrolyte influences the ohmic components of the dissipation factors, since a higher conductivity results in a reduction of the dissipation factor. However, an increase in conductivity generally involves a reduction in breakdown voltage. Accordingly, the simultaneous presence of high conductivity and high breakdown voltage is contradictory.
Soviet Union Patent No. 303662 discloses an operating electrolyte for aluminum electrolytic capacitors consisting of a mixture of 10 to 120 parts by weight of ethylene glycol, 1 to 10 parts by weight of boric acid, 1 to 10 parts by weight of adipic acid, 2 to 10 parts by weight of ammonia and 1 to 2 parts by weight of phosphoric acid. However, this electrolyte does not exhibit sufficient conductivity to appropriately reduce the dissipation factor of electrolytic capacitors containing such electrolyte.